fluid mosaic model

Question 1

name all 8 components within the cell membrane (phospholipid bilayer)

Answer 1

phospholipids, cholesterol, intrinsic proteins, extrinsic proteins, glycolipids, glycoproteins, protein channels and carrier proteins

Question 2

describe the phospholipids within the cell membrane

Answer 2

have a hydrophilic head and hydrophobic tail. They’re arranged in a bilayer with their heads out and tails in

Question 3

describe the role of phospholipids within the cell membrane

Answer 3

don’t allow water soluble molecules through. Small, non-polar substances and water can diffuse through the membrane

Question 4

describe the structure of cholesterol in the cell membrane

Answer 4

type of lipid that fits between the phospholipids. Contains polar/hydrophobic regions.

Question 5

describe the role of cholesterol in the cell membrane

Answer 5

it gives the membrane stability and makes it more rigid. Creates a further barrier stopping polar molecules. reduces fluidity and permeability of the cell membrane.

Question 6

where can you find intrinsic proteins in the cell membrane?

Answer 6

span across both bilayers as either protein channels or carrier proteins

Question 7

describe the role of intrinsic proteins in the cell membrane

Answer 7

involved in the transport of molecules across the membrane. Creates pores in which water and water soluble chemicals can pass through. Act as carriers in active transport

Question 8

where can you find extrinsic proteins in the cell membrane?

Answer 8

the surface of the membrane

Question 9

describe the role of extrinsic proteins in the cell membrane

Answer 9

form receptor sites for hormones. They’re are important in cell recognition and provide structural support. Attached to lipids and proteins to form glycoproteins and lipids

Question 10

what is a glycolipid?

Answer 10

lipids that have a carbohydrate branch attached to it

Question 11

describe the role of glycolipids in the cell membrane

Answer 11

involved in cell to cell signalling and self recognition. This is important in the immune system response and recognising bacterial invasions

Question 12

what is a glycoprotein?

Answer 12

proteins that have a carbohydrate branch attached to it

Question 13

describe the role of glycoproteins in the cell membrane

Answer 13

involved in cell to cell signalling and self recognition. This is important in the immune system response and recognising bacterial invasions

Question 14

describe the role of protein channels in the cell membrane

Answer 14

form tubes that fill with water to enable water soluble ions to diffuse

Question 15

describe the role of carrier proteins in the cell membrane

Answer 15

bind with larger molecules and change shape to transport them to the other side of the membrane.

Question 16

what molecules CAN pass through the membrane?

Answer 16

lipid soluble substances (eg some hormones)
small molecules (eg CO2, O2, H2O)

Question 17

what molecules CANT pass through the membrane?

Answer 17

water soluble (polar) substances (eg sodium ions)
large molecules (eg glucose)